The invention is in the field of quarter, half, or full turn valves like butterfly or ball valves. There are various types of actuators available to turn the shaft of valves. There are actuators where the rotatable shaft of the valve is actuated by an acme drive screw or by ninety degree pneumatic actuators such as Keystone actuators. There are pneumatic rack and pinion rotary actuators; where racks are mounted at ninety degrees to the pinion on the shaft of the valve; pneumatic scotch yoke actuators; and a helical groove design actuator manufactured by Helac Corporation (Enumclaw, Washington). There are also eccentric multi-gear actuators. Engineers have tried to incorporate as many utilizable features in the actuators as possible. Thus it is an object of this invention to provide a universal actuator which will meet the wider needs of the industry.
It is an object of this invention to provide an actuator which is compact, economical; concentric and symmetric to the shaft of the valve in its geometrical design, and has an axial orientation in the direction of the shaft which drives the valve.
It is an object of this invention to provide an actuator which readily can be modified to meet the various requirements of valves, while retaining its central core feature.
It is another object of this invention to provide an actuator which is efficient and can provide maximum torque, with respect to its relative size, compared to other actuators.
It is another object of this invention to provide manual override which is self locking.
It is another object of this invention to provide an actuator having dependable fail safe closure, by means of springs, in the event of electric or air supply failure.
It is another object of this invention to provide an actuator which can be actuated by hydraulic or pneumatic means, or by means of an electric motor, or manually.
It is another object of this invention to provide an actuator which can incorporate in its design multi-springs in multi-locations of its body.
It is another object of this invention to provide an actuator where springs can quickly and easily be taken out from any chamber or cavity or cavities to modify the functions of the actuator.
It is another object of this invention that the parts of the actuator can be inspected or replaced readily in the field when the manual override drive takes control of the valve.
It is also an object of this invention to provide an actuator where a number of springs and their reaction time can be changed to provide customized torque output to a specific application.
It is another object of this invention that the actuator can also be operated hydraulically by reversible pump.
It is another object of this invention that the actuator will have a minimum number of moving seals.
According to the invention, an axial actuator has a body made of two integrated concentric cylindrical enclosures of differential height. The space above the inner enclosure is divided by a piston disk into two parts, and a third part includes space which lies inside and around the inner enclosure. Thus, said three parts create three chambers A, B, and C in the axial direction of the shaft of the valve; chamber A being farthest from the valve, chamber B being the intermediate chamber, and chamber C being nearest to the valve, around the shaft of the valve. A cavity is also provided to encircle said inner enclosure.
Under the first alternative, said chambers and said encircling cavity around the inner enclosure accommodate synchronized functionary means. These means include a piston disk between chambers A and B and a compression spring in chamber B, which reacts against said piston disk. Also included, in chamber C nearest to the valve, is a main bevel gear, which is connected to the shaft of the valve by means of its hub while its teeth are engaged with bevel pinions of compounded pinions supported by the inner enclosure. On the opposite ends of said compounded pinions are spur pinions engaged with rack gears which project axially like arms from the rim of said piston disk into said cavity encircling chamber C. Also, said cavity encircling Chamber C is shared by compression springs which react against said piston disk. The compounded pinion is an assembly of two pinions having a spur pinion gear on one end and a bevel pinion gear on the other end of a common shaft. By actuating said piston all the synchronized functionary components are actuated to actuate the shaft to open or to close the valve.
Under the second alternative, individual cavities are provided for compression springs. There are also individual cavities provided for spur pinions which are engaged with the rack gears. Said individual cavities lie on a circle around Chamber C. The difference between this second alternative, compared to the first, is that the wall of the inner enclosure is now integrated with the wall of the outer enclosure. The height of the inner cylindrical enclosure is designed to be less than the height of the outer cylindrical enclosure by a predetermined difference to accommodate the stroke of the piston which divides Chamber A from Chamber B. The piston can be actuated by various means: pneumatic, hydraulic, an electric motor, or compression springs. Other means include using a screw shaft, a shaft having helical grooves around its outer surface, or a worm and a worm gear override drive. The actuator of the invention is designed on the principle that the vertical distance the rack gears travel, in unison, must produce the desired quarter, half, or full turn of the shaft of the valve through synchronous means; said synchronous means being the compounded pinions, the main bevel gear and compression springs.
If a customer needs it, the actuator can be provided with a manual override drive. The manual override drive consists of a shaft which is driven from outside the actuator; two spur gears and two worms held in tandem around a worm gear, where said worms act as a couple to rotate said worm gear which is integrated with the main bevel gear in chamber C. Said worm gear rotates the shaft of the valve. As the actuator is designed to meet universal needs of quarter turn valves, the invented actuator can easily be modified in the shop or in the field according to the needs of the customer.